Radio frequency identification (RFID) systems have been proposed for identifying tagged objects for such purposes as taking inventory or tracking movements of objects being transported. Examples are described in U.S. Pat. Nos. 6,097,301, 5,300,875; 5,365,551; and 5,448,110.
As known in the prior art, and as described by Tuttle in his U.S. Pat. No. 6,097,301 entitled RF Identification System with Restricted Range which issued Aug. 1, 2000, RFID systems generally employ a passive or active RF transceiver, called a “tag”, mounted on each object to be identified or tracked.
Conventional RFID systems provide little or no interactive feedback in response to actions for example those performed by human operators. Specifically, conventional RFID systems lack any means for discriminating in favor of an individual tagged object that a human operator is working with at any given moment; instead, conventional RFID systems generally would confuse the operator by providing information regarding all the tagged objects in the vicinity. Furthermore, if a number of personnel are working close to each other, conventional RFID systems cannot direct information about a tag to the specific individual who is handling the tagged object.
By way of one example, suppose a number of postal personnel are sorting or routing tagged packages according to the destination encoded in a tag attached to each package. Conventional RFID systems lack any means for detecting which individual package a human handler is about to pick up so as to provide to the operator only the destination or routing information for the package that person currently is handling, to the exclusion of information about other nearby packages.
By way of a further example, locating a single automobile parked in so-called vehicle distribution centers where tens of thousands of such automobiles may be parked in a dense array is conventionally a time consuming task which is prone to trial and error and which would using conventional prior art RFID systems preclude detecting the single sought after automobile to the exclusion of information about other nearby vehicles.